[steveklabnik]

It is a combination of both. We took performance into consideration when designing all aspects of the langauge, and so we've laid a lot of groundwork. The gains have come because the compiler had so much technical debt; imagine a hundreds of thousands of LOC codebase where the language changes out from under it on a weekly/daily basis. So every since 1.0, and even before, really, it's been paying off debt, and doing things in better ways. And there's more coming. Incremental recompilation will make after-the-first compiles go even faster. But all of that takes tons of work.

[Gankro]

On the other hand, niko has described trait resolution as "basically prolog", so that's something you can push to perform as degenerately bad as you want (the recent addition of specialization only making things worse).

The issue is just how degenerately bad "most" code is -- and I think that hinges a lot on how excited the word "higher" gets you vis-a-vis expressing your programs. If you think C# is a pretty cool type system that doesn't afraid of anything you'll probably be fine. If you think scala or haskell with All The GHC Extensions is where it's at... watch out.

[tatterdemalion]

> I think that hinges a lot on how excited the word "higher" gets you vis-a-vis expressing your programs.

You are the best Gankro. <3

What's nice about coherence is that there's little risk in modifying the constraint solving algorithm to optimize for the common use cases (because it can't be backward incompatible). What's nice about crater is that it's comparatively easy to test that optimization.